The invention relates to multiport ball valves for fluid handling.
Multiway valves are known to comprise a valve casing having a valve shaft disposed within them. Typically, a valve casing has a substantially cylindrical fluid or gas chamber and inlet and outlet ports for introducing and discharging fluids and the shaft has a fluid passage that can connect the inlet port with one of the outlet ports. Rotation of the valve shaft switches fluid passage in the valve.
For example, U.S. Pat. No. 5,109,877 discloses a multiway valve in which multiple balls valves are disposed in the interior of the valve. In one embodiment of this valve, two or more balls disposed along a length of a valve shaft are used to regulate the flow of fluid through the ports. The valve shaft (e.g. a cam shaft) is rotatably inserted into a valve casing. The valve shaft may be rotated to displace the ball from a position blocking the outlet port. The fluid flows generally around the rotating valve. With the outlet port unblocked, liquid may be channeled through the valve into a desired channel.
U.S. Pat. No. 4,934,408 discloses a ball valve in which a ball may be moved from a position blocking a port by a rotatable lever. This device uses a single ball for all ports. The shaft of the lever holds a valve basket that is matched to the width of the ball. This allows the shaft to displace the ball from the port when the valve is rotated.
In order to produce a valve able to withstand high pressures, the valves of the prior art tend to incorporate many elements and are thus complex to assemble and quite costly.
It is an object of the present invention to provide a new and improved multiport valve that is durable, relatively inexpensive to manufacture, relatively easy to assemble and that has the capability of allowing for and blocking the flow of fluid, including a highly pressurized fluid, between an inlet port and an outlet port.
It is another object of the present invention to provide a multiport valve having discrete flow circuits.
It is a further object of the present invention to provide a multiport valve having a stable valve cylinder that is durable and relatively easy to rotate without damaging the cylinder.
The above object is achieved in a multiport valve featuring a rotating valve cylinder having a channel with a nested portion or depression for receiving a ball biased toward the cylinder. The rotating cylinder is disposed within an opening in the valve casing, the casing having fluid inlet and outlet ports for introducing fluid into and discharging fluid from the valve casing. The term xe2x80x9cfluidxe2x80x9d is meant to encompass any fluid, gas or other material desired to be used in conjunction with the valve of the present invention. An O-ring or other type of seal is disposed adjacent to the outlet port. Rotating the valve cylinder such that the nested portion aligns with the ball, forces the biased ball into the nested portion and away from the seal, thus opening the outlet port. Rotating the valve cylinder such that the nested portion is misaligned with respect to the depression causes the channel or a portion of the channel to contact the ball and to overcome the bias and force the ball against the seal, thus closing the outlet port. Any number of ports may be used. Discrete flow circuits between select ports are formed when the valve cylinder is rotated. The arrangement and number of depressions within the valve cylinder and the arrangement and number of ports determine which ports are part of the flow circuit or act as inlet or outlet ports. If a port is not adjacent to a ball, it is an inlet port when provided with fluid flow. Alternatively a port having a ball adjacent to it may also be an inlet port. The arrangements may vary as desired.
In one embodiment, a bearing is disposed in between the cylinder and the valve casing. A ball biasing member, for example a spring, is angled obtusely or acutely relative to a longitudinal axis of the cylinder, such that an end of the spring is directed toward the cylinder. Forces from the spring biased ball converge to the bearing and the bearing in turn applies the forces to the cylinder. Therefore, in order to turn the cylinder, only the force from the bearing need be overcome. This arrangement provides for a decrease in the amount of force necessary to operate the cylinder. Additionally, this arrangement improves the stability of the valve member and decreases the possibility of damaging the valve member during rotation without involving expensive solutions utilized in the prior art.